Gravity flow grain dries

ABSTRACT

The disclosure describes a dryer for granular material provided with first and second successive zones to treat the material with heated gas under dehydrating conditions and a third zone connected therewith wherein the material is treated with incoming cool gas, characterized by passageways to conduct the flow of gas in opposite directions transversely through the first and second zones and means to combine the effluent gases from the second and third drying zones and supply heat thereto to form the heated gases used in the first and second zones. In one embodiment the granular material is passed successively through the first, second and third treating zones, the supply of cool gas is conveyed into the third zone to cool the dehydrated material therein, the effluent gases from the cooling zone are passed to a heating zone to form a portion of the dehydrating gas passed to the first and second zones while the effluent from the second zone is being recycled to the heating zone to be mixed with the effluent from the cooling zone and the effluent from the first zone is being exhausted from the system. In another embodiment the granular material is passed downwardly by gravity through perforated columns arranged in a vertical substantially parallel relationship, and a baffle system surrounds the columns to provide a division of the heated treating gas, between the first and second zones, whereby a portion of the gas is directed outwardly from between the columns in the second zone and then recirculated while the remainder of the gas is directed inwardly through the perforated columns of the first zone from which it is discharged as the effluent from the system. Other embodiments are disclosed including means to control the volume of recycled effluent from the second treating zone, e.g., the proportion of moisture laden gas sent to the heating zone for recirculation.

Unite States Patent James P. Lavalier Mahtomedi, Minn. 762,750

Sept. 26, 1968 Dec. 28, 1971 Hart-Carter Company Chicago, 111.

lnventor Appl. No. Filed Patented Assignee GRAVITY FLOW GRAIN DRIES 6Claims, 9 Drawing Figs.

US. Cl

Int. Cl

Field of Search Primary Examiner-Frederick L. Matteson AssistantExaminer-Harry B. Ramey Attorney Rummler & Snow ABSTRACT: The disclosuredescribes a dryer for granular material provided with first and secondsuccessive zones to treat the material with heated gas under dehydratingconditions and a third zone connected therewith wherein the material istreated with incoming cool gas, characterized by passageways to conductthe flow of gas in opposite directions transversely through the firstand second zones and means to combine the effluent gases from the secondand third drying zones and supply heat thereto to form the heated gasesused in the first and second zones. ln one embodiment the granularmaterial is passed successively through the first, second and thirdtreating zones, the supply of cool gas is conveyed into the third zoneto cool the dehydrated material therein, the effluent gases from thecooling zone are passed to a heating zone to form a portion of thedehydrating gas passed to the first and second zones while the effluentfrom the second zone is being recycled to the heating zone to be mixedwith the effluent from the cooling zone and the effluent from the firstzone is being exhausted from the system. In another embodiment thegranular material is passed downwardly by gravity through perforatedcolumns arranged in a vertical substantially parallel relationship, anda baffle system surrounds the columns to provide a division of theheated treating gas, between the first and second zones, whereby aportion of the gas is directed outwardly from between the columns in thesecond zone and then recirculated while the remainder of the gas isdirected inwardly through the perforated columns of the first zone fromwhich it is discharged as the effluent from the system. Otherembodiments are disclosed including means to control the volume ofrecycled effluent from the second treating zone, e.g., the proportion ofmoisture laden gas sent to the heating zone for recirculation.

PATENTED M82819?! SHEET 1 BF 3 AOUTSIDEI Column Thickness //Vl/ENTOR.JAMES P. LA VAL/ER Pmmmnmamn 3529.954

SHEET 3 BF 3 /62 IN A /84 OUTDOOR FROM FAN FROM \TO FAN \FAN/ M54 m d/ae11m 1 FAN h I/VVENTOR.

JAMES PLAV/IL/ER GRAVITY FLOW GRAIN DRIES BACKGROUND OF THE INVENTION Itis known to dry granular material by countercurrent contact with aheated gas. Where the granular material is a grain such as wheat or corncareful consideration must be given to the frangible nature of theparticles along with through-put, that is the number of bushels of thegrain treated per hour and the drying efficiency, where the goal isgenerally the removal of a predetermined amount of moisture so that thegrain can be properly stored and subsequently processed.

Prior art dryers or dehydrators for general industrial use take avariety of forms that differ generally from grain dryers which must ofnecessity be capable of processing large volumes of grain in shortperiods of time and with the least expense. Accumulations of brokengrain kernels within the system must be prevented, the devices must beeasily maintained and cleaned, and the dehydration process must besubject to finite control. Uneven heating of the grain causes thekernels to crack or check. Part of these difficulties have been overcomeby controlling the temperature of the incoming air, and by dividing theeffluent air from the initial contact with the grain and directing aportion thereof to a subsequent contacting zone coadjacent to the finalcooling zone. Also, the prior art uses mechanical vibrators, alternateinlet and exhaust ports and various air distributing means to direct thedehydrating air through the grain.

As will be demonstrated herein, the efficiency of these prior dryers inaccomplishing a reduction of the water content of corn, for example fromabout 25 percent to about percent, is about 3,500 B.t.u. per pound ofwater evaporated. However, the moisture content of the corn is unevenacross the grain drying column.

In accordance with this invention an apparatus for drying granularmaterial is provided which attains the desired goal of water removalwithout uneven drying of the material and at a reduced heat consumptionwhile at the same time increasing the through-put per unit of time.These results are accomplished without introducing mechanical problemsor using complicated flue and column systems.

SUMMARY OF THE INVENTION In accordance with this invention a plural zonedryer for granular material is provided wherein the granular material iscontinuously subjected to preheated dehydrating gas in a first andsecond treating zone, wherein the direction of flow of the gas inrelation to the granular material is transverse the body of granularmaterial in each zone, but in opposite or different directions, the flowof incoming cool dehydrating gas is transverse the body of granularmaterial in a succeeding zone and the gases conveyed to a first and asecond or intermediate zone comprises a preheated mixture of l coolinggases or effluent from the next successive zone and (2) at least aportion of the effluent from a second or intermediate zone. In oneembodiment the proportion of such recycled effluents is adjusted byfinite control of the respective volumes of each so that the desiredmoisture removal for a particular granular material is maintainedwithout sacrifice of uniformity of moisture loss across the column ofgranular material. This objective is accomplished by providing anadjustable flue between the second or intermediate zone and thesuccessive or last zone of treatment.

DESCRIPTION OF THE DRAWINGS One embodiment of this invention is shown inthe drawings by way of illustration wherein:

FIG. 1 is a perspective view of the exterior housing for a grain dryeradapted to contain the component parts of the device ofthis invention.

FIG. 2 is a side elevational view, slightly enlarged and partially cutaway to show the interior construction;

FIG. 3 is a schematic view illustrating, by means of arrows and partsshown in their simplest form, the path and relative amounts ofdehydrating gases passing through the dryer of this invention;

FIG. 4 is a schematic view of the device of this invention with thesides broken away to show an illustrative flow path of dehydrating gasesthrough the treating zones;

FIG. 5 is a cross-sectional view taken along the lines 55 of FIG. 2;

FIG. 6 is a cross-sectional view taken along the lines 6-6 of FIG. 2;

FIG. 7 is a cross-sectional view taken along the lines 77 of FIG. 2;

FIG. 8 is an end view of the device shown in FIG. 2 with the outer wallremoved; and

FIG. 9 is a graph with the percentage of water loss as the ordinate andpercentage of column thickness as the abscissa depicting andsupplementing the comparative data of example I.

THE PREFERRED EMBODIMENTS Referring to the drawings the housing 10represents any form of exterior structure having sidewalls 12, end walls14 and roof structures 16 and 18 adapted to contain dehydrating gases,provide shelter for the equipment and supporting structure for the fluesand treating zones arranged in accordance with this invention. Forsimplicity of description the invention will be described in relation toa grain or corn dryer adapted to be installed out of doors in connectionwith the storage silo and related equipment with which it is used.However, it is to be understood that the means and steps to be describedin whole or in subcombination can be applied to any type of granularmaterial and various modifications, some of which will be mentioned, canbe made in the apparatus to adapt the same to dehydration of other foodstuffs and other granular materials. Accordingly, the invention will bedescribed using gravity flow of grain and it will become apparent thatother means for conveying the granular material through the treatingzones, such as mechanical conveyors, can be used with little alterationof the flue system or the means and steps for its operation.

The housing 10 supports the conduit 20 at its top which communicates tothe inlet zone 22 (FIG. 8) under the roof [8, same constituting thegrain inlet. The conduit 20 is connected at its other end to the bottomof a storage bin or silo (not shown) representing the source of grain tobe dried. Exterior of the housing 10 and supported by thereof 16 againstthe intermediate wall 24, is the main flue 26 which communicates at thebottom 28 (FIG. 2) with the discharge conduit 30 of the blower 32. Themotor 34 represents a source of power operating the blower 32 throughthe belt drive 36. A suitable bracket support 38 is provided to mountthe blower 32 in this relationship. The intake port of the blower 32 isrepresented at 40 and a regeneration zone or source of heat for thegases, in this instance air, is represented at 42 with the fuel beingsupplied through the pipe 44 controlled by suitable metering devices(not shown).

As shown in FIG. 8 the housing 10 provides support for a pair of graincolumns 50 and 52 each comprising spaced perforate screen walls 54 and56 and having a bottom 58 communicating with the inlet of a screwconveyor 60 or other suitable means for transporting the dehydratedgrain to a storage means (not For purposes of orienting the relativepositions of the parts in the respective views some of the parts whichare identical are given prime numbers, e.g., the walls 54' and 56' ofthe columns 52.

The outer walls 54 of the respective columns 50 and 52 extend upwardlyto the under side of the roof l8 defining the grain inlet zone 22,therebetween, as shown in FIG. 8. The inner walls 56 converge asindicated at 62 to form a divider so that the grain falls into eachcolumn evenly. The rate of input of the grain through the conduit 20 issubstantially equal to the rate of withdrawal by the conveyor means .60so that a constant level of grain is maintained and at least a part ifnot all of the converging top 62, is covered with grain.

The main section of both walls 54 and 56 in each column below the levelof the grain are perforated. For this purpose, these walls can befabricated of any material which has suffi cient strength and chemicalinertness to support the grain columns and also withstand thetemperatures involved in the dehydration process. For this purposestainless steel plate or wire screening can be used having evenly spacedopenings therein which are of lesser area than the average or smallestsize of the grain being processed. Generally, perforations or openingsabout five sixty-fourths inches in diameter are suffcient for grain assmall as rice.

Referring to F IG. 8 a first or topmost transverse floor or baffle 66 isprovided extending across the housing 10. The baffle 66 is imperforateand is made up of the two outer sections 68-68 and an inner section 70.This divides the top part of the housing into the first treating zone orsection 72 through which the dehydrating gases pass in the direction ofthe arrows and in a manner to be described.

A second, lower floor or imperforate baffle 74 is provided spaced fromthe baffle 70 and above the bottom 58 of the grain columns 50 and 52.The inner portion 76 of this baffle, between the grain columns 50 and52, is stationary and the outer portions 78-78 are hinged at their inneredges 80, by any suitable means, so as to be pivotal downward from theessentially closed full line position to the open or dotted linepositions as shown. The baffle 74 divides the housing into the secondzone or intermediate section 82 through which the dehydrating gases passin the direction of the arrows and in a manner to be described.

The foregoing arrangement of baffles 70 and 76 divides the housing 10into the first and second treating zones with the flow of gases beingrelatively opposite directions through the grain columns 50 and 52 asillustrated by the respective arrows. Thus, in the construction shown,the flow of gases in the first zone 72 is from the outer plenum chambers84-84 inwardly through the grain. The flow of gases in the zone 82 isoutwardly through the grain and into the chambers 86-86. The plenumchambers 84-84 and 86 are separate and do not communicate within thehousing except, possibly, through the grain columns 50 and 52.

The third zone 92 of the housing 10 is defined between the baffle 74 andthe bottom wall 94 and, like the second zone, has corresponding outerchambers 96-96.

Referring to FIGS. 2 and 7, the backwall 14' has a cool gas or airintake opening 100 which communicates directly with the zone 92 and theimperforate opposite wall member 102 closes off this chamber and causesthe cool gas to pass outwardly through the grain columns and, beingconfined by the sidewalls 12, this gas then passes into the inlets 40 ofthe blower 32 which, as shown, is a double-inlet device. The outlet ordischarge end of the blower conveys the airstream past the burner 42,within the main flue 26 and upwardly over the top of the intermediatewall 102 where a portion of the gas enters into the zone 82 as indicatedby the arrows. The wall member 102 can be constructed of sheet metal andmay form the backwall of the flue 26.

Means to arrest any sparks or burning material within the main flue 26are provided at 105, same being transverse a1- temate, spaced bafflesproviding a tortuous path for the heated air.

Within the zone 82 the air passes through the grain columns 52 outwardlyinto the chambers 86 above the movable baffler 78. The baffle 70prevents the air from progressing upwardly and it is diverted downwardlythrough the spaces 106-106 into the chambers 96, where it mixes withpartially heated air from the zone 92 and is recycled back to the blower32.

As shown in FIG. 1 the main flue 26 divides just above the baffle 76into the bypass conduits 108-108 which divide the remaining airstreaminto two parts and conveys them upwardly to the respective outerchambers 84-84 of the zone 72 whence the air passes inwardly through thegrain columns 52 into the interior chamber and then through the louveredoutlet 110 to atmosphere. The louvered outlet 110 is constructed withinthe wall 24 and is of such an area as to avoid any backpressure buildup.

The relationship of the parts and the flow of the airstrcams through thecolumn is better indicated by reference to F168. 3 and 4 wherein thewidth of the airpaths is adjusted to approximate the relative volume ofeach stream. As shown, the incoming cool airstream 112 passes into thezone 92, divides into substantially equal streams 114-114, and passesvia the chambers 96 to the respective inlets 40 of the blower 32.

As shown, the discharge stream 116 from the blower passes through themain flue 26 upwardly past the heater 42 and the heated stream dividesin the flue 26, approximately 50 percent of the stream, represented at118, passing into the interior of the zone 82, and thence outwardlythrough the grain columns, on each side, into the chambers 86-86 whereinthe recycle streams are formed and pass through the baffle openings106-106 to form the second half of the recycle stream 122. The remaininghalf of the main heated airstream 116, as indicated at 118, passesupwardly in the flue 26 and divides into the flues 108-108, to form thestreams 124-124 which pass into the chambers 84 of the zone 72 andthence inwardly through the grain columns to be combined and dischargedas the system effluent stream 126.

A representative volumetric relationship between the airstreams is shownin table I in a typical drying operation along with the possiblevariations using a blower 32 having a In order to further demonstratethis invention, the following examples and comparative test data aregiven.

EXAMPLE 1.

A first grain dryer A representing one of the typical prior art dryerswas compared with a prototype dryer B of this invention. The dryer A wasconstructed with elongated spaced parallel grain columns 50 and 52within a housing 10 and with variable speed discharge conveyors 60 atthe bottom. This dryer has a cooling section 92 at the bottom whereinair at atmospheric conditions was drawn into and passed through thecolumns 50 and 52 as in the instant invention, that is, from the insideto the plenums 96. The air was taken up by the blower 32 and sent to anddistributed along a single zone 82 which comprised the entire hot-airdryer section. Basically the grain dryer A was like the prototype Bexcept that the zone 72 was not present, that is there was no wall 70and there was no recycle stream 120 or stream 124. Rather, the entirevolume of drying air was passed through the grain and discharged to theoutside. The grain dryer A bad a rated capacity of 750 bushels per hour(BPH) drying corn from a moisture content of about 20 percent to amoisture content of about 15 percent.

The prototype dryer B was of exactly the same physical size as the DryerA and the effective air flow areas of the drying zone 82 of dryer A wasthe same as the combined flow areas of the zones 72 and 82 of the dryerB.

The table 11 following shows the conditions of operation, the capacitiesand the end results of treating corn from the same bulk source in thesetwo dryers.

As seen from the results shown in table 11 both dryers were operated at200 F. and the overall goal of reducing the moisture content of the cornfrom 25 percent to 15 percent by weight for a 10 percent water loss orremoval was attained. However, the throughput of the dryer B of thisinvention was 500 BPl-l (wet basis) or 1,000 BPH after adjustment for 5percent drying. This is almost double the capacity of the dryer A. Thisis reflected in the increase in the pounds of water evaporated per hourwhich is again almost double. Furthermore, these results are attainedwith only an increase in fuel consumption of 400,000 B.t.u. per hour andless CFM of air discharged to the atmosphere. Most important the testresults show that the moisture content of the finished corn taken fromthe inside, middle and outside sections of the corn columns in the dryerA varied by 6.2 percent with the minimum variation being 5.1 percent. Incontrast the prototype dryer B maintained a percent variation inmoisture content across the column from the inside corn to the outsidecorn and only a 1.0 percent variation as a maximum from the middle ofthe column in either direction. This data is shown graphically in FIG. 9where outside is the side of the column at which the dehydrating airenters the grain. An important factor in the economy of the dryer Bresides in the recirculation of 50 percent of the drying air whichresults in a maximum water content of the exhausted air as well as thefurther advantage of a minimum of heat-shock" on the grain as it entersthe dryer.

EXAMPLE II.

The dryer of this invention is used to dry corn having 20 percent waterat a drying temperature of about 195 F. using outside air having arelative humidity of about 195 F. using outside air having a relativehumidity of 60 percent and at a temperature of about 61 F. About 500 BPH(wet basis) or 1,000 BPH (adjust for percent drying) can be treatedunder these conditions to bring the moisture content to about 10 percentwith a variation across the column of less than 1.0 percent for thefinished corn.

EXAMPLE Ill.

The process of example 1 is conducted using wheat having a moisturecontent of percent and the end product has a moisture content of 10percent with less than 1.0 percent variation in moisture content acrossthe column.

It is apparent from the foregoing that this invention can be carried outunder a variety of conditions while still attaining the increasedthroughput, reduced heat consumption and uniformity of the moisturecontent of the end product. The

method of this invention is carried out by treating a granular materialto the following steps:

1. subjecting a flowing mass of granular material, traveling a singlecontinuous path, to contact with a portion of regenerated fluid agent ina first zone under condition to bring about a partially changed product,the fluid agent passing through the granular material in a directiontransverse the direction of the flowing mass.

2. Subjecting the partially changed product of the first zone totreatment with another portion of regenerated fluid agent in a secondzone to produce a substantially changed product, the fluid agent passingtransversely through the granular material in a direction opposite thatof the first zone.

3. subjecting the substantially changed product of the second zone totreatment with fresh heating agent in a subsequent zone under conditionsto bring about a final desired change and produce the finished granularmaterial and then 4. combining and recycling the effluent treating agentfrom the second zone and from the subsequent zone to a regeneration zonewhereby to form the portions of regenerated treating agent for deliveryto the first and second zones respectively.

As applied to the problem of controlled dehydration of grain as thegranular material, the fluid agent is air or other gas inert under theconditions imposed, the desired changes are water removal and finalcooling, and the regeneration is the application of heat.

As heretofore mentioned, the portion of the dehydrating medium which isrecycled from the second zone to the next subsequent zone is subject tovariation depending on the nature of the dehydrating medium, ambient oratmospheric conditions where air is used, the degree of dehydration tobe obtained and the flow capacity of the system employed. For mostoperations this portion can vary from about 30 percent to about 70percent of the fluid capacity of the system. In applying this inventionto the drying of grain the foregoing values will apply and for mostoperations the recycled portion can be 50 percent of the totalthroughput of air. The proportioning is accomplished by variation of theopenings 106 afforded by the baffle plates 78. This expedient can beused to increase the recycled stream 120 when the humidity of theincoming air stream 112 is in the order of percent and decrease therecycled portion when the humidity of the airstream 112 is below 90percent. In other words the portion or amount of recycled air isadjusted to the dehydrating capacity of the drying medium.

A wide variety of continuous physical and chemical changes can bebenefited by applying the process or using the apparatus of thisinvention. The requirements of intimate and uniform fluid-solid contactalong with the conservation of any energy introduced under conditions ofmaximum fluid volumes for a number of processes can be met and improvedresults obtained by applying the opposite and transverse flow of thefluid treating agent in the first and second treating zones inconjunction with recycling a controlled and variable portion of thecombined effluent treating agent from the second and a third or asubsequent treating zone to the regeneration zone.

It is apparent that one conveyor means represented by the opposedperforate wall members 54 and 56, can be used within a column or otherform of enclosure including the plurality of treating zones while stillmaintaining the transverse and opposite flow feature in the first andsecond zones along with the recycling and combined effluent techniquefor the second and third zones. The flow of the treating agent in thezone 72 can be reversed in relation to the flow direction shown for thezone 82 in the drawings. This would require that the duct 108 functionsto convey the fluid streams 124 and 124 into the zone 72 between thegrain columns of this treating zone and that the plenums 84 and 84 beopen to the atmosphere on one of their sides. Also, to accomplish therecycle feature, the dampers 78 and 78 between the pair of graincolumns, as in the baffle 76. The air intake 100 would be divided andplaced so that each half communicated with the plenums 96 and 96' whilethe wall 102 would be provided with a passageway and duct communicatingwith the inlet of the blower and with the recycled effluent from thecentral damper of the zone 82. Other modifications become apparent toone skilled in the art. i

lclaim:

1. An apparatus for contacting a fluid treating agent comprising,

a. a series of successive enclosed treating zones including a firstzone, a second zone and a third zone, each of said zones having opposedspaced walls defining an individual chamber,

would be positioned particulate solid with a b. conveyor means toconduct said solid through said treating zones successively, from firstto second and then to third, and adapted to contain said solid as adivider extending across the chamber of each of said treating zones,

veyor means providing through said chambers,

d. said outlet opening of said first treating zone discharging directlyto atmosphere and being on the same side of said conveyor means as theinlet opening of said second treating zone and the outlet of said secondtreating zone communicating directly with the outlet of said thirdtreating zone,

e. a regeneration zone for said treating agent communicatsecond treatingzones and including means for forcing flow of treating agenttherethrough,

. said third treating zone having an inlet for entry of fresh treatingagent thereinto and g. means to control the flow volume of treatingagent through the outlet of said second treating 2. An apparatus inaccordance with claim 1 in which,

a. said conveyor means extends as an elongated column in a substantiallyvertical relationship through said treating zones b. means are providedto continuously supply said solid to the top of said conveyor means andwithdraw said solid from the bottom thereof, and

c. said conveyor means comprises perforate walls adapted to retain saidparticular solid material and allow the passage of said fluid throughsaid walls and into intimate contact with said solid material.

3. An apparatus in accordance with claim I in which,

a. said regeneration zone is a heating zone.

4. An apparatus in accordance with claim 1 in which,

a. said means for forcing flow of said treating agent is a fluid pumphaving its inlet connected to the outlet of said third treating zone.

5. An apparatus in accordance with claim I wherein,

a. a pair of said conveyor means is provided extending in spacedrelationship from each other and having spaced perforate wallscontaining the particulate solid therebetween,

b. means are adapted to receive and discharge granular material, acontinuous uninterrupted column within said housing adapted to conveysaid granular solid from said inlet to said outlet as a continuousflowing stream,

0. said column having spaced perforate walls confining said flowingstream of granular solid therebetween,

d. bafile means dividing said housing member into three verticallysuccessive and separate treating zones between said inlet and saidoutlet, the first zone being uppermost,

lets of the second and third zones and the gas outlet of the first zonedischarging to atmosphere,

f. a passageway through the baffie means between said second and thirdheating zones on the gas outlet side of said column,

g. means within said passageway to control the flow rate of saiddehydrating gas therethrough, and

b. means for introducing fresh gas to the gas inlet side of the thirdzone.

UNKTED STATES PATENT OFFICE CERHMCATE Q35 QQRRECHQN Patent No D d I 28pInventor(s) P a-1.162

I It is certified that error appears in the above-identified patentandthat said Letters Patent are hereby corrected as shown below:

The following errors were committed by the Patent Office:

The title should be "Gravity Flow Grain Drier".

Column 3, line 41, "86 should read "86-86.

fiolozrm 7,, line 35, should read "treating agent therein-to, and".

Column 7, line 37, zonefl should appear after "treating".

Column 3 line 41., should read "zonesfi'.

Signed and sealed this 30th day of May 972.,

{SEAL} Attest:

EDWARD MaElE'IGHER JRQ ROBERT GOTTSGHALK Atteeting Officer Commissionerof Patents

1. An apparatus for contacting a particulate solid with a fluid treatingagent comprising, a. a series of successive enclosed treating zonesincluding a first zone, a second zone and a third zOne, each of saidzones having opposed spaced walls defining an individual chamber, b.conveyor means to conduct said solid through said treating zonessuccessively, from first to second and then to third, and adapted tocontain said solid as a divider extending across the chamber of each ofsaid treating zones, c. each of said chambers of said treating zoneshaving an inlet and an outlet opening on opposite sides of said conveyormeans providing a passageway for fluid to pass through said chambers, d.said outlet opening of said first treating zone discharging directly toatmosphere and being on the same side of said conveyor means as theinlet opening of said second treating zone and the outlet of said secondtreating zone communicating directly with the outlet of said thirdtreating zone, e. a regeneration zone for said treating agentcommunicating between the outlet of said third treating zone and theinlets of said first and second treating zones and including means forforcing flow of treating agent therethrough, f. said third treating zonehaving an inlet for entry of fresh treating agent thereinto and g. meansto control the flow volume of treating agent through the outlet of saidsecond treating
 2. An apparatus in accordance with claim 1 in which, a.said conveyor means extends as an elongated column in a substantiallyvertical relationship through said treating zones b. means are providedto continuously supply said solid to the top of said conveyor means andwithdraw said solid from the bottom thereof, and c. said conveyor meanscomprises perforate walls adapted to retain said particular solidmaterial and allow the passage of said fluid through said walls and intointimate contact with said solid material.
 3. An apparatus in accordancewith claim 1 in which, a. said regeneration zone is a heating zone. 4.An apparatus in accordance with claim 1 in which, a. said means forforcing flow of said treating agent is a fluid pump having its inletconnected to the outlet of said third treating zone.
 5. An apparatus inaccordance with claim 1 wherein, a. a pair of said conveyor means isprovided extending in spaced relationship from each other and havingspaced perforate walls containing the particulate solid therebetween, b.means are provided for directing the treating agent through the twoconveying means in respectively opposite directions in the firsttreating zone and in the reverse directions through the respectiveconveying means in the second and third treating zones, c. the outlet ofsaid first treating zone is between said spaced conveyor means, d. theinlet of said second treating zone is between said spaced conveyormeans, and e. the inlet of said third treating zone is between saidspaced conveyor means.
 6. An apparatus for crosscurrent contacting of agranular solid with a dehydrating gas which comprises, a. a verticalhousing having a top inlet and a bottom outlet adapted to receive anddischarge granular material, b. a continuous uninterrupted column withinsaid housing adapted to convey said granular solid from said inlet tosaid outlet as a continuous flowing stream, c. said column having spacedperforate walls confining said flowing stream of granular solidtherebetween, d. baffle means dividing said housing member into threevertically successive and separate treating zones between said inlet andsaid outlet, the first zone being uppermost, e. means providing a gasinlet to and a gas outlet from each of said treating zones with the gasinlet of the first zone being on the opposite side of said column thanthe gas inlets of the second and third zones and the gas outlet of thefirst zone discharging to atmosphere, f. a passageway through the bafflemeans between said second and third heating zones on the gas outlet sideof said column, g. means within said passageway to control the flow rateof said dehydrating gas theRethrough, and h. means for introducing freshgas to the gas inlet side of the third zone.